BOSTON Big changes are underway at the Boston Symphony Orchestra as it officially begins its search for a new music director. Wednesday afternoon the organization announced that maestro James Levine is stepping down.

“People are sad,” Volpe said at Symphony Hall. “You know those first two years were incredible, and then he started one after another, after another… ”

Volpe was referring to Levine’s recurring health issues, which are well-known to Boston audiences at this point. They’ve plagued the conductor, the orchestra and fans of the BSO for years.

Recovery periods that followed surgeries on herniated discs forced Levine to cancel a slew of appearances. He missed more than half of the season last year, which forced Volpe and the BSO staff to scramble for fill-in conductors.

All of the injury problems have fueled speculation about the maestro’s future with his orchestra, and the question came to a head last week, Volpe said, in the 11th hour before a big performance of Mahler’s “9th Symphony.”

“He was in a lot of pain,” Volpe recalled. “He tried to take some medicines to deal with the pain and it was not a good situation.”

Levine could not take the podium, and on Tuesday announced he was bowing out for the rest of the current season. Then came Wednesday’s announcement that Levine would step down as music director for good.

“I think he came to the realization that, institutionally, another major absence was going to be untenable for the institution, and untenable for the musicians,” Volpe explained.

And untenable for ticket sales, which have dropped. Whether the dip is because of all the uncertainty is unclear, but something had to be done, Volpe said.

Levine did not respond to request for comment after the news broke, but Volpe assured observers that he and the maestro started talking seriously about this possible solution last November — and the decision was a joint one. Even so, Volpe admitted he is still in a bit of shock.

“The surreal part is, at this moment in time, I knew Jim needed to reduce his schedule significantly,” Volpe said. “I just told the orchestra what was going on and certainly there was concern for his well-being, but they weren’t surprised.”

Longtime classical music editor of the Boston Phoenix Lloyd Schwartz felt the same way, especially after learning that Levine canceled his appearances during the BSO’s upcoming, long-planned East Coast tour that was supposed to be led by the maestro.

“I wasn’t exactly surprised,” Schwartz said. “I had a feeling that this latest cancellation, especially since it involved not just performances in Boston but at Carnegie Hall and the Kennedy Center, that this was probably just the last straw.”

Fact is, Levine has a busy schedule in New York starting at the end of the month — at his other job. He’s also the music director for the Metropolitan Opera Orchestra in New York. Peter Gelb is the general manager there.

“The impact on the Met is somewhat different,” Gelb explained. “It’s not really comparing apples to apples. An opera company like ours is different than a major symphony orchestra.”

Levine is still on the program for performances of “Das Rheingold” at the Met, where Gelb said Levine is just one of a cast of many characters involved in the massive production.

When asked about managing the potential risk that Levine could cancel those performances, Gelb replied, “There is inherent risk in opera because there are so many moving parts. Fact is, maestro Levine’s attendance record is probably far greater than any singers’ here because singers do cancel quite often.”

Levine is celebrating 40 years with the opera’s orchestra. But will his duties or schedule change at all after news of Levine’s stepping down at the BSO?

“The plan is that they are not changing,” Gelb said.

The changes for Levine and the BSO here in Boston are a big concern for many, especially for Schwartz, the classical music observer.

“I hope they can find someone as close to his level of musicianship as they possibly can,” Schwartz said.

That search has officially begun, according to Volpe, but he wouldn’t say if they already have a replacement in mind.

“First of all, that would be presumptuous of me since the search committee hasn’t even met, hasn’t started talking names,” Volpe said. “But I think right now it’s wide open.”

And who knows — the Boston Symphony Orchestra’s next music director might very well have filled-in during one of Levine’s absences over the years.